When you have an algorithm, it tends to favor some posts over others which in some cases is good but in other cases is oh so bad. The higher problem is the visibility of the algorithm misbehaving is reduced, so you're likely not even aware of how bad the problem is.

Rather than have an algorithm and trying to hide any problems, Mastodon puts the problems front and centre. You are forced to deal with them. It makes you spend a little bit of time controlling your feed's hygiene and in return you end up with a feed that only contains useful content.

It's like the eating healthy alternative to doomscrolling.

It also has another interesting side effect. Not having an algorithm that concentrates on popularity means that the low effort content problem tends to evaporate away. Attention seekers aren't rewarded for spamming or rage baiting, since they lose followers every time they try.